FIG. 1 is a schematic illustration of a magnetic recording device, such as an HDD 100, according to one embodiment of the present disclosure. The HDD 100 includes at least one magnetic recording medium, such as a disk 102 that is supported on a spindle 104. A motor causes the spindle 104, and hence the disk 102, to rotate. One or more magnetic heads 106 are mounted on a slider 108 and move over the disks 102 to read and write information from and to the disks 102. The heads 106 ride on an air bearing in close proximity to the disks 102 during read and write operations. The slider 108 is coupled to an actuator 110 by a suspension 112. The suspension 112 provides a slight spring force which biases the slider 108 towards the disk surface. Each actuator 110 is attached to an actuator means 114 that controls the movement of the head 106 relative to the disk 102. A HDD ramp 116 is positioned such that when the actuator 110 rotates the slider 108 and head 106 away from the disk 102, the heads and slider can “park” on the HDD ramp 116.
The disk 102 is formed on either a glass or an aluminum alloy substrate depending on the particular design requirements of the device. The disk 102 (also referred to as the media) is configured to be usable at high recording densities, and in some embodiments, to be used in the Perpendicular Magnetic Recording (PMR). The media thus stores data in which the bits of magnetic moment orient in substantially perpendicular direction to the surface of the disk 102.
FIG. 2 depicts a conventional magnetic recording media with a non-magnetic seed layer. As shown in FIG. 2, the magnetic media 102 may generally include some or all of the constituent layers shown in FIG. 2, including a substrate 202, a bottom soft magnetic underlayer (SUL) 204 and a top SUL 208 separated by an AFC coupling layer 206, a non-magnetic seed layer 210, an intermediate layer 212, a magnetic recording layer 214, a cap layer 216 and an overcoat layer 218.
The top SUL layer 208 and the bottom SUL layer 204 are magnetically coupled through the antiferromagnetic coupling layer (AFC) 206. The bottom SUL 204, AFC coupling layer 206 and top SUL 208 are also referred to as the SUL structure 220. The recording layer 214 and the soft under layers 204 and 208 provide a magnetic circuit that allows magnetic flux to travel from the magnetic recording head 106 through the magnetic recording layer 214 and the soft underlayers 204 and 208, back to the magnetic recording head, thus forming a loop. Additionally, the SUL layers 204 & 208 allow for increasing conductance of magnetic flux through the magnetic media 102 and therefore improve writabilty of the magnetic media 102. However, the writabilty of the magnetic media 102 further improves if the distance between the magnetic recording head 106 and the top SUL 208 is as small as possible.